PURPOSE: To obtain a gas detecting element having the low temp. coefft., of resistance by containing a prescribed quantity of SiO2, Al2O3, MgO, PtCl in SnO2, calcining them by hot pressing method and providing a RuO2 system electrode thereto.

CONSTITUTION: 0.1W20wt% silicon oxide, 0.1W30wt% aluminum oxide, 0.1W 5wt% magnesium oxide and 0.1W10wt% platinum chloride are added to a stannic oxide powder and mixed therewith, then calcined to 600W1,000°C temp. under 100W1,000kg/cm2 impressing pressure by hot pressing method to form a gas sensitive body 1. Ruthenium oxide system thick film resistance paste having 10Ω/squareW10Ω/square sheet resistance is painted to the body 1, said body is baked at 600°C to form an electrode 2, and the gas detecting element is obtained. The temp. coefft. (1/R.ΔR/ΔT) of said element is 5.1×10-3/°C in 1,000ppm gaseous isobutane.